The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Modeling and Detection of High Impedance Arcing Fault in Medium Voltage Networks

Nagy Ibrahim Elkalashy

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 26th of November, 2007, at 12 noon.

Overview in PDF format (ISBN 978-951-22-9015-4)   [3259 KB]
Dissertation is also available in print (ISBN 978-951-22-9014-7)

Abstract

In this dissertation, a universal arc representation using the Electromagnetic Transient Program (EMTP) is first developed. It is accomplished based on the bilateral interaction between EMTP network and Transient Analysis Control System (TACS) field. This arc modeling procedure is used as a useful guide to present a new model for high impedance arcing faults due to leaning trees. At the Power Systems and High Voltage Laboratory, Helsinki University of Technology (TKK), Finland, experiments have been performed to measure the fault characteristics due to leaning trees and therefore to verify the proposed model. Towards investigating detection facilities of this fault type, the fault model is incorporated at different locations in 20 kV Medium Voltage (MV) networks using the ATPdraw program, which is a graphical interface utilized to simplify the ATP/EMTP processing. Then, phase quantities and residual components are taken at different measuring nodes in the simulated networks. It is revealed that the main feature of this fault type that can enhance its detection is the periodicity of electromagnetic transients created by repetitions of the arc-reignition after each current zero-crossing. This feature is obtained considering different earthing concepts. Different detection techniques are proposed based on Discrete Wavelet Transform (DWT). The absolute sum of the wavelet coefficients in the respective frequency band is investigated for the detection purposes while several selectivity functions are proposed for the first time. The selectivity functions are presented using Logic Functions, fundamental current components and transient power directionalities. Test cases provide evidence of the efficacy of the proposed techniques.

This dissertation is written in a form of the article dissertation. Its core depends on both of a summary and six original publications.

This thesis consists of an overview and of the following 6 publications:

  1. H. A. Darwish and N. I. Elkalashy, Universal Arc Representation Using EMTP, IEEE Transactions on Power Delivery, vol. 20, no. 2, pp. 772-779, April 2005. © 2005 IEEE. By permission.
  2. N. I. Elkalashy, M. Lehtonen, H. A. Darwish, M. A. Izzularab and A.-M. I. Taalab, Modeling and Experimental Verification of High Impedance Arcing Fault in Medium Voltage Networks, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 14, no. 2, pp. 375-383, April 2007. © 2007 IEEE. By permission.
  3. N. I. Elkalashy, M. Lehtonen, H. A. Darwish, M. A. Izzularab and A.-M. I. Taalab, DWT-Based Investigation of Phase Currents for Detecting High Impedance Faults Due to Leaning Trees in Unearthed MV Networks, 2007 IEEE Power Engineering Society General Meeting, Tampa, Florida, USA, June 24-28, 2007. © 2007 IEEE. By permission.
  4. N. I. Elkalashy, M. Lehtonen, H. A. Darwish, A.-M. I. Taalab and M. A. Izzularab, DWT-Based Extraction of Residual Currents Throughout Unearthed MV Networks for Detecting High-Impedance Faults Due to Leaning Trees, European Transactions on Electrical Power, ETEP, vol. 17, no. 6, pp. 597-614, November/December 2007. © 2007 John Wiley & Sons. By permission.
  5. N. I. Elkalashy, M. Lehtonen, H. A. Darwish, A.-M. I. Taalab and M. A. Izzularab, A Novel Selectivity Technique for High Impedance Arcing Fault Detection in Compensated MV Networks, European Transactions on Electrical Power, ETEP, in press, published online on 23 April 2007, DOI: 10.1002/etep.179. © 2007 John Wiley & Sons. By permission.
  6. N. I. Elkalashy, M. Lehtonen, H. A. Darwish, A.-M. I. Taalab and M. A. Izzularab, DWT-Based Detection and Transient Power Direction-Based Location of High Impedance Faults Due to Leaning Trees in Unearthed MV Networks, The 7th International Conference on Power Systems Transients, IPST 2007, Lyon, France, June 4-7, 2007. © 2007 IPST Conference. By permission.

Errata of publications 3, 5 and 6

Keywords: arc models, earth faults, high impedance arcing faults, fault detection

This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.

© 2007 Helsinki University of Technology

Last update 2011-05-26